Magnetic resonance spectroscopy (1H MRS) and imaging (MRI) were used to investigate the effects of a bout of moderate prolonged exercise on intra (IMCL)- and extramyocellular lipid (EMCL) utilization in the soleus, tibialis anterior, and gastrocnemius muscles of five trained human subjects. MRI and 1H MRS measurements were obtained before and after a 90 min run on a calibrated treadmill at a velocity corresponding to 64±1.5% of each subjects' maximal rate of oxygen consumption. There were significant decreases in IMCL following exercise in the tibialis (pre: 22.37±4.33 vs. post: 15.16±3.25 mmol/kg dry wt; P<0.01) and soleus (pre: 36.93±1.45 vs. post: 29.85 ±2.44 mmol/kg dry wt; P<0.01) muscles. There was also a decrease in the gastrocnemius muscle, although this did not reach the level of significance (pre: 33.78±5.35 vs. post: 28.48±5.44 mmol/kg dry weight; P<0.10). No significant changes were observed in EMCL or subcutaneous fat. In conclusion, this study showed that IMCL were significantly utilized in the tibialis and soleus muscles of aerobically endurance-trained humans. The absence of significant utilization of IMCL in the gastrocnemius may reflect differences in fiber type and/or intensity of contraction for each muscle group.

The Potential of Omega-3 Supplementation to Reduce Muscle-Inflammation after Muscle-Damaging ExerciseKyriakidou, Y., Kantorovich, R.C., Bell, J.D., Monterisi, S. and Dolci, A. 2017. The Potential of Omega-3 Supplementation to Reduce Muscle-Inflammation after Muscle-Damaging Exercise. ACSM Annual Meeting, World Congress on Exercise is Medicine & World Congress on the Basic Science of Exercise and the Brain. Denver, Colorado 30 May - 03 Jun 2017 American College of Sports Medicine. doi:10.1249/01.mss.0000518523.15295.1c